This "Mycarta-ring commutator" attached to an 8-coil DC pulse motor's shaft is made using 4 brass screws at 90 degrees imbedded into the mycarta around the rim as contacts, then thesee brass screws are filed smooth around the surface.
Two spring-loaded carbon motor brushes, one in each rotating plastic sleeve, contact these brass-contacts in order to complete circuit. This design will complete a circuit a total of 8 times per rotation, since there are two brushes, and four contacts.
Rotating sleeves made of 4" plastic plumbing caps that rotate to adjust timing of each brush, shown here pulled apart:
Commutator with the 2 carbon brushes that can now be individually adjusted in their timing:
